Solar supercapacitors could power wearable sensors

Researchers from the University of Glasgow’s Bendable Electronics and Sensing Technologies (BEST) group have developed a promising new type of graphene supercapacitor, which could be used in the next generation of wearable health sensors.

Currently, wearable systems generally rely on relatively heavy, inflexible batteries, which can be uncomfortable for long-term users. The BEST team, led by Professor Ravinder Dahiya, have now built on their previous success in flexible sensors by developing a supercapacitor which could power health sensors capable of conforming to wearers’ bodies, offering more comfort and a more consistent contact with skin to better collect health data.

Described in the journal Nano Energy, the supercapacitor uses layers of flexible, three-dimensional porous foam formed from graphene and silver to produce a device capable of storing and releasing around three times more power than any similar flexible supercapacitor. Demonstrating its durability, the team showed that the supercapacitor provided power consistently across 25,000 charging and discharging cycles.

The BEST group also found a way to charge the system by integrating it with flexible solar-powered skin they had previously developed, effectively creating an entirely self-charging system. The system was subsequently and successfully utilised to continuously power a pH sensor which uses the wearer’s sweat to monitor their health.

“We’re very pleased by the progress this new form of solar-powered supercapacitor represents,” Professor Dahiya said. “A flexible, wearable health monitoring system which only requires exposure to sunlight to charge has a lot of obvious commercial appeal, but the underlying technology has a great deal of additional potential.

“This research could take the wearable systems for health monitoring to remote parts of the world where solar power is often the most reliable source of energy, and it could also increase the efficiency of hybrid electric vehicles. We’re already looking at further integrating the technology into flexible synthetic skin which we’re developing for use in advanced prosthetics.”